windows截屏

 #ifndef _CAPTURESCREEN_H
 #define _CAPTURESCREEN_H

 #include <windows.h>
 class  CaptureScreen
 {
 public:
     CaptureScreen()
     {};
     ~CaptureScreen(void)
     {};

     void ScreenInit();
     void ScreenFree();
     bool ScreenSetWindow(LPRECT lpRect);
     bool ScreenCopy(BYTE *dstBuf); 

     int rHeight;    //要获得的图像尺寸
     int rWidth;
 private:
     int nScreenWidth;
     int nScreenHeight;
     PRGBTRIPLE scan0;
     BITMAPINFO pbi;
     int stride;
     int top_x;
     int top_y;
     int bot_x;
     int bot_y;
 };

 #endif

 #include "CaptureScreen.h"

 void CaptureScreen::ScreenInit()
 {
     nScreenWidth = GetSystemMetrics(SM_CXSCREEN);
     nScreenHeight = GetSystemMetrics(SM_CYSCREEN);

     pbi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
     pbi.bmiHeader.biWidth = nScreenWidth;
     pbi.bmiHeader.biHeight = nScreenHeight;
     pbi.bmiHeader.biPlanes = ;
     pbi.bmiHeader.biBitCount = ;
     pbi.bmiHeader.biCompression = BI_RGB;
     stride = ((nScreenWidth *  + ) & 0xffffffe0) / ;  // 24位图像扫描线宽度
     scan0 = (PRGBTRIPLE)malloc(stride * nScreenHeight);    // 图像数据缓冲区，应释放
 }

 void CaptureScreen::ScreenFree()
 {
     free(scan0);
 }

 bool CaptureScreen::ScreenSetWindow(LPRECT lpRect)
 {
      top_x = lpRect->left;
      top_y = lpRect->top;
      bot_x = lpRect->right;
      bot_y = lpRect->bottom;
     if(top_x >= bot_x)
     return false;
     if(top_y >= bot_y)
     return false;
     if(top_x< || bot_x>nScreenWidth)
     return false;
     if(top_y< || bot_y>nScreenHeight)
     return false;

     rHeight = bot_y-top_y;
     rWidth =  bot_x-top_x;
     return true;
 }

 bool CaptureScreen::ScreenCopy(BYTE *dstBuf)
 {
     HWND hDesktopWnd = GetDesktopWindow();
     HDC hDesktopDC = GetDC(hDesktopWnd);
     HDC hCaptureDC = CreateCompatibleDC(hDesktopDC);
     HBITMAP hCaptureBitmap =CreateCompatibleBitmap(hDesktopDC,nScreenWidth, nScreenHeight);
     SelectObject(hCaptureDC,hCaptureBitmap);
     BitBlt(hCaptureDC,,,nScreenWidth,nScreenHeight,hDesktopDC,,,SRCCOPY|NOMIRRORBITMAP);
     DeleteDC(hCaptureDC);

     GetDIBits(hDesktopDC, hCaptureBitmap, , nScreenHeight, scan0, &pbi, DIB_RGB_COLORS);
     ReleaseDC(hDesktopWnd,hDesktopDC);
     DeleteObject(hCaptureBitmap);

     BYTE *srcBuf = (BYTE*) scan0;

     int j;
     srcBuf += (nScreenHeight--top_y)*stride+top_x*;// scan0倒序
     for(j=;j<rHeight;j++)
     {
         memcpy(dstBuf,srcBuf,rWidth*);
         dstBuf += rWidth*;
         srcBuf -= stride;
     }
     return true;
 }

 #include "CaptureScreen.h"
 #include <stdio.h>
 #include <Mmsystem.h>
 #pragma comment( lib,"winmm.lib" )
 void SaveBmp2(BYTE *bgr32,int w,int h,int mode)
 {

     /////////////////////////////////////////////
     DWORD size=w*h*;
     LPSTR lpData=(LPSTR)GlobalAlloc(GPTR,size);
     /////////////////////////////////////////////
     BITMAPINFOHEADER bih;
     bih.biSize=sizeof(BITMAPINFOHEADER);
     bih.biWidth=w;
     bih.biHeight=h;
     bih.biPlanes=;
     bih.biBitCount=;
     bih.biCompression=;
     bih.biSizeImage=w*h*;//size;
     bih.biXPelsPerMeter=;
     bih.biYPelsPerMeter=;
     bih.biClrUsed=;
     bih.biClrImportant=;

     BITMAPFILEHEADER bfh;
     bfh.bfType=0x4D42;  // "BM"      // 设置位图文件头
        bfh.bfReserved1=bfh.bfReserved2=;
     bfh.bfSize=+size;
     bfh.bfOffBits=;

     if(mode == )
     {
     for(int i=;i<h;i++)
     {
         memcpy(lpData+(h--i)*w*,bgr32+i*w*,w*);
     }
     }
     else
         memcpy(lpData,bgr32,w*h*);

     static int filecount=;
     char filename[];
     sprintf(filename,"C:\\%d.bmp",filecount);
     FILE *fp=fopen(filename,"wb");

     if(fp)
     {

         fwrite(&bfh,,sizeof(BITMAPFILEHEADER),fp);
         fwrite(&bih,,sizeof(BITMAPINFOHEADER),fp);
         fwrite(lpData,,size,fp);
         fclose(fp);
         filecount++;
     }
     GlobalFree(lpData);

 }

 int main()
 {

     CaptureScreen myCapture;
     myCapture.ScreenInit();
     RECT dstRect={,,,};
     myCapture.ScreenSetWindow(&dstRect);
     BYTE *dstBuff = (BYTE*)malloc(myCapture.rWidth*myCapture.rHeight*);
     int lastTime = timeGetTime();
     myCapture.ScreenCopy(dstBuff);
     printf("time:%dms",timeGetTime()-lastTime);
     SaveBmp2((BYTE*)dstBuff,myCapture.rWidth,myCapture.rHeight,);
     myCapture.ScreenFree();

     return ;
 }